Sofa



FIG. 1 is a front elevational view of a sofa;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right elevational view thereof;

FIG. 4 is a left elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a front, left perspective view thereof.

The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a sofa, as shown and described. 